9cm

I know this is in Danish, but down at the bottom, there's an illustration that should make some sense (At least I can get some understanding from it although whether my understanding is correct is another matter.), provided you know Europeans like to use a decimal comma instead of a decimal point (their 17,5 is our 17.5). Some Danish scientists have found that the 2002 finding that Yding Skov was the highest point in Denmark is incorrect. Actually Møllehøj is 9cm taller. That's 3.5 inches.